Device for controlling a winch provided with a safety device

ABSTRACT

This invention relates to the control of a winch connected to a hydraulic motor which comprises two conduits connected, the first to a source of pressurized fluid or to a discharge tank, the second to the tank or to the source, this control comprising a brake provided with a control member selectively connected by a third conduit to the source and to the tank. A calibrated valve is disposed on the conduit, downstream of the connection of the conduit to the delivery of the source. This control is suitable for being adapted to the circuit for adjusting the position of the hook of a crane.

United States Patent .1191

Jacob 1 Oct. 2, 1973 1 DEVICE FOR CONTROLLING A WINCH PROVIDED WITH ASAFETY DEVICE [75] lnventor: Rene F. Jacob, Lagny Le Sec (oise),

France [73] Assignee: Societe Anonyme: POCLAIN, Oise,

France [22] Filed: Mar. 8, 1972 [211 App]. No.: 232,688

[30] Foreign Application Priority Data Mar. 17, 1971 France 7109417 [52]US. Cl 303/22 R, 188/170, 303/11 [51] Int. Cl Fl6h 57/10 [58] Field ofSearch 303/10, 11, 13, 22 R; 188/170 [56] References Cited UNITED STATESPATENTS 3,305,277 2/1967 Pickles et a1 303/11 X 3,472,560 10/1969Desthuilliers 303/13 3,516,525 6/1970 Skaggs 188/17OX PrimaryExaminer-Allen N. Knowles Assistant Examiner-Michael Mar Att0rneyErnestA. Greenside [57] ABSTRACT This invention relates to the control of awinch connected to a hydraulic motor which pomprises two con; duitsconnected, the first to a source of pressurized fluid or to a dischargetank, the second to the tank or to the source, this control comprising abrake provided with a control member selectively connected by a thirdconduit to the source and to the tank. A calibrated valve is disposed onthe conduit, downstream of the connection of the conduit to the deliveryof the source.

This control is suitable for being adapted to the circuit for adjustingthe position of the hook of a crane.

4 Claims, 4 Drawing Figures DEVICE FOR CONTROLLING A WINCH PROVIDED WITHA SAFETY DEVICE The present invention relates to a device for,controlling a winch provided with a safety brake.

Certain types of winches are already known which, when the control ofthe winch ceases to act, are immobilized by a safety brake.

ln hydraulically controlled winches, a hydraulic motor is coupled to thewinch and has one of its chambers selectively placed in communicationeither with a source of pressurised fluid, or with a discharge tank. Inthis category of winches, the release of the safety brake is generallycontrolled by a jack, the feed of winch is connected to the mainhydraulic circuit controlling the motor of the winch.

This state of affairs results firstly in that said jack, and, moregenerally, the member for controlling the safety brake, must berelatively large in order to develop a force under the effect of thelowest pressure of the fluid contained in the admission conduit of themotor of the winch, of sufficient value for releasing-the brake. lt isto be borne in mind that the lowest pressure referred to hereinabove,during the turning of the winch, occurs during the turning without load(for example when the hook of a crane rises empty, without suspendedload). Another result, which is a secondary consequence of the precedingarrangement, is that the dimensions of the circuit for communicating themember controlling the brake with the discharge tank, during a braking,must also'be large, in order to create only reduced pressure drops whenthe fluid leaves said member, and thus in order to brake as quickly aspossible.

In brief, the heretofore known embodiments necessitate choosing largecontrol members for the safety brakes.

The invention intends to remedy this state of affairs, and to this endproposes a new winch controlling device. The hydraulic drive motorcoupled with thewinch comprises two conduits connected respectively andselectively by means of an at least two-way distributor, the first to asource of pressurized fluid in the position of the distributorcorresponding to. the turning of the winch, and to a discharge tank whenthe distributor is in its position opposite that corresponding to theturning, the second to the discharge tank and to the source ofpressurized fluid, the control device, comprises a safety brake providedwith a control member selectively connected, by a third conduit, to saidsource of pressurized fluid and to said discharge tank.

A calibrated valve is disposed on said first conduit,

downstream of the connection of said third conduit to.

the delivery of the source of pressurized fluid with respect to saidsource of pressurized fluid.

ln addition, when said distributor is in the position corresponding tothe turning of the winch, the opening of said calibrated valve isadvantageously controlled, by known means by the value of the pressureof the,

fluid contained in the part of the first conduit located downstream ofsaid calibrated valve withrespect to. the source of pressurized fluid.

Finally, when the control device comprises in addition a speed limiterdisposed on the firstconduit, and this speed limiter has a section ofpassage which is adjustable, when the distributor is in the positionopposite that corresponding to the turning, asa function of the value ofthe pressure of the fluid contained in the second conduit, thecalibrated valve is preferably constituted by said speed limiter.

The invention will be more readily understood upon reading the followingnon-limiting description with reference to the accompanying drawings, inwhich:

FIG. 1 is a schematic section of a first embodiment of adevice accordingto the invention;

FIGS. 2, 3 and 4 are schematic sections of a secon variant of a deviceaccording to the invention, but in three distinct positions of thecontrol distributor of the winch.

Referring now to the drawings, the device shown in FIG. 1 comprises awinch which, in the present case, is referenced by its hydraulic drivemotor 1. A safety brake is constituted by its brake lining 2, disposedopposite the winch. The lining 2 is articulated about the axis 3 and isnormally maintained in abutment on the winch with the aid of an elasticholding member 4. A jack 5 is, furthermore, coupled between thestructure 6, on which is mounted the winch and the lining 2. When thelower chamber 5a of the jack 5 is fed with pressurized fluid, said jack5 develops a force opposite to that of the elastic member 4. It will benoted that the chamber 5b of the jack 5, opposite chamber 5a, is permanently connected to a discharge tank 7 by a conduit 8.

The motor 1 comprises two conduits 9 and 10, of which conduit 9 mayconstitute either the fluid admission or delivery conduit depending uponthe direction of rotation of the winch. Thus when the winch turns in onedirection, for example when the hook of the crane coupled to said winchrises conduit 9 acts as a fluid admission conduit and when turned in theopposite acts as a fluid delivery conduit, a conduit 10' iscomplementary of conduit9, that is, when conduit 9 delivers conduit 10admits fluid and vice versa.

Conduits 9 and 10 are selectively connected to delivery conduit 11 of apump 12, whose suction conduit 13 is connected to the discharge tank 7,and to said tank 7 by means .of a conduit 14, respectively, and viceversa, by means of a three-way distributor 15.

It will be noted that a valve 16, which comprises a calibrated spring17, is in series connection with the conduit 9. The conduits 9 and 10 onthe one hand and 11 and 14 on the other hand, are connected to thedistributor 15 which ensures the following communicating connections: inits first position, the conduit 11 with conduit 14, by isolatingconduits 9 and 10; in its second position, conduit 9 with conduit 11 andconduit 10 with conduit 14; finally, in its third position, the conduit10 with-conduit 11 and conduit 9 with conduit 14.

A conduit 18 furthermore connects chamber 5a of the jack 5 to thedelivery conduit 11 of the pump 12, while-a conduit 19, is connectedbetween the conduit 18and'to the valve 16. Said valve 16 comprises aslide 20 -which is subjected to the oppositely directed forces impartedby the calibrated valve spring l7 and the pressure of the fluidcontained in conduit 19.

The slide 20 of the valve 16 comprisesin addition a shoulder 21 capableof being displaced based the edge 22 of a groove 23 in the body 24 ofthe valve 16, while the part of the conduit 9, connected to the motor 1,

I, opens into said groove 23. The second part of conduit 9"whichis'connected to the distributor 15, opens into asecond groove 25, alsofound in body 24. The slide 20 by virtue ofithe portion of shoulder 21ensures either the isolation of two grooves 23 and 25 or communicationtherebetween by means of the section of passage constituted by the spacebetween the edge 22 of the groove 23 and said shoulder 21, said sectionof passage having a value that varies from a'zero section to a sectionwithout pressure drop, adjusted as a function of the position occupiedby the slide 20 which is balanced under the antagonistic actions of thespring 17, and of the pressure of the fluid contained in the conduit 19,said pressure acting on the face 26 of a piston 27 coupled to said slide20.

An advantageous variant embodiment is shown in FIG. 2, in which thecommon elements of FIG. 1 are provided with the same reference numerals.What is noteworthy, in this embodiment, is the presence of one or morereceivers, other than the motor 1 of the winch, which fed by a singlepump 12. In this embodiment, a jack 28 is connected by conduits 29 and30 to the feed circuit of the winch. To this end, a three-waydistributor 31 is interposed in the delivery conduit 11 of the pump 12between said pump and the distributor 15. A more detailed description ofthis modification is not deemed necessary since the use of additionaldistributors are well-known. Suffice it to say that in view of the jack28 a two-way distributor 32 is interposed on the conduit 18. The slideof this distributor 32 is mechanically coupled, in the example shown, tothe slide of distributor 15, so that there corresponds to the firstposition of distributor 15, in which the conduit 11 is placed incommunication with the conduit 14, a first position of distributor 32,in which the parts of the conduit 18 located upstream and downstream ofsaid distributor 32 are isolated from one another. Furthermore in thefirst position of the distributor 32 chamber a of jack 5 is connected tothe tank 7 by a conduit 33.

It will be specified that the mechanical connection of the slides of thedistributors and 32 is ensured by means of a cam 34 with two apices,separated by a notch 35, on which a roller 36 is in permanent abutment,mounted to rotate on a rod 37 integral with the slide of the distributor32. The double-apex cam 34 is biased for movement with the distributorslide by means of rod 38, a spring 39 acting on distributor 32 forurging the roller 36 in abutment on the cam. In the arrangement of FIG.2, the roller 36 is disposed in the notch 35 of the cam.

In the showings of FIGS. 3 and 4,-which respectively illustrate theslide of thedistributor 15 disposed in its second and third positions,the cam has been displaced with said slide of the distributor 15, sothat the roller 36 is, in each of these two cases, disposed on one ofthe apices 34. The slide of the distributor 32 has therefore been urgedrearwardly and is disposed in its second position, in which the conduit33 connection at distributor 32 is broken while the conduit parts 18 arein communication and connect the chamber 50 of the jack 5 to conduit 11.

Another feature of the embodiment of FIGS. 2 to 4 will now bedistributed. The conduit 19 has been eliminated, and instead a conduit40, is connected on the one hand and between that portion of conduit 9disposed between valve 16 and distributor l5, and on the other hand tothe face 26 of piston 27. In addition, a supplementary groove 41 isprovided in the body 24. In this embodiment the conduit 10 is separatedinto two parts the groove 41 being disposed therebetween. The piston 27is furthermore distinct from the slide 20, with which piston 42 isintegral. The face 43 of the piston 27, which is opposite face 26, isthus opposite the face 44 of piston 42. Furthermore, the face 44 ofpiston 42 is permanently subjected to the action of the pressure of thefluid contained in groove 41.

In FIG. 2, as well as in FIG. 1, it is to be noted that, with thedistributor 15 disposed in its first position, the chamber 5a is placedin communication with the discharge tank 7, by conduits 18, 11 and 14 inone case, 18 and 33 in the other case. The elastic holding member 4therefore acts alone on the lining 2 which is accordingly in firmabutment on the winch.

In FIGS. 3 and 4, the chamber 5a is on the on the other hand placed incommunication, by conduit 18, with conduit 11. The action of the jack 5in such circumstances overcomes the action of the elastic member 4, sothat the lining 2 is separated from the winch.

In FIG. 2, the spring 17 of the valve 16 acts independently on the slide20, which it urges to the right as viewed in the drawing therebyisolating the two parts of conduit 9.

In FIG. 3, the action of spring 17 is opposed by the pressure of thefluid acting on the face 26 of the piston 27. Consequently, a passage 45is provided between the edge 22 of the body 24 and the shoulder 21 ofthe slide 20. The face 43 of the piston 27 is in abutment with the face44 of the piston 42.

Finally, in FIG. 4, the action of the spring 17 is opposed by that ofthe pressure of the fluid on the face 44 of the piston 42. This samepressure has, moreover, pushed the piston 27 rearwardly as viewed in thedrawing. A passage 46, is then provided between the edge 22 of the body24 and the shoulder 21 of the slide 20. The pistons 27 and 42 are nowseparate.

The operation of the devices described will be apparent from thefollowing.

Concerning first of all the device shown in FIG. 1, the distributor 15may be disposed in one of its three positions.

In its first position, shown in this figure, the winch is isolated fromthe tank 7 and from the pump 12. The pump 12 discharges into conduit 11which returns to tank 7, through the intermediary of distributor 15 andconduit 14. The pressure in conduit 11 is thus zero (except for pressuredrops) and the pressure of the fluid in conduit 18 and in chamber 5a ofjack 5 is therefore also zero. The brake lining 2 is accordingly inabutment with the winch under the action of the elastic holding member4. Furthermore, the pressure in the conduit 19 is also zero so that,under the action of spring 17, the slide 20 is pushed back and isolatesthe two parts of conduit 9 from one another.

In its second position, the slide of the distributor 15 is pushedtowards the right with respect to the position that it occupies inFIG. 1. The pump 12 with the distributor so displaced discharges intoconduit 11, in the first part of conduit 9 and into the groove 25, whichmomentarily does not open out into groove 23. The pressure of the fluidtherefore increases in conduit 11, as well as in conduits 18 and 19. Thepiston 27 is therefore acted on by the the pressure of the fluid on itsface 26. The slide 20 moves towards the left, until a passage isprovided between the edge 22 and the shoulder 21. The fluid in thegroove 25 therefore passes through the passange into groove 23, andconnects with the second part of conduit 9, to cause the motor 1 and,thus the winch, to rotate, the connection of the motor 1 is completed byconduit 10, distributor l5, conduit 14, leading to the tank 7.

With the connections just described, either the winch turns under load a(heavy mass lifted by the hook of a crane), or the winch turns withoutload (hook of the crane rising alone).

If the winch is under load, the pressure in the groove 23 and in thesecond part of the conduit 9 is high. The passage between the edge 22and the shoulder 21 having been opened, remains open virtually withoutpressure drop, because the pressure is also high in conduits ll, 18 and19. Under these conditions the pressure on the face 26 of the piston 27overcomes the bias effect of the spring 17.

If, the winch is separated under no load conditions, a low pressure inthe groove 23 and the second part of conduit 9 will suffice to cause thewinch to turn. In this case, the pressure is relatively low in thegroove 23 and falls, with respect to its initial value, in the firstpart of the conduit 9 and conduits 11, 18 and 19. The force on the face26 of the piston 27 diminishes, and the spring 17 returns the slide 20towards its initial position (towards the right). The passage betweenthe edge 22 and the shoulder 21 is thereby narrowed, but not closed, andconstitutes thereby a restriction with pressure drop: the value of thepressure in the groove 25 being higher than the value of the pressure inthe groove 23. The pressure in the conduits l1, l8 and 19 is thereforestabilized to a value determined as a function of calibration of thespring 17. In the present case, whilst the pressure in the groove 23 isa few bars (for no load conditions), the spring 17 has been chosen sothat the pressure in the groove 25 is equal to 50 bars.

The advantage of the device described resides in. In the previousembodiments, the pressure of a fluid in for example conduit 11 couldonly be 5 bars. Accordingly, to overcome the effect of the elasticmember 4, a large section for jack 5 had to be provided which inconsequence required within its chamber 50 a large quantity of fluid.When the winch was immobilized and the safety brake made operative, thefluid previously introduced into the chamber 5a had to be evacuated,this requiring, this provision of large section conduits for conduits18, 11 and 14 in order to avoid counterpressures. With the device ofFIG. 1, the pressure in the conduit 11 is never lower than 50 bars. Infact, either the pressure in the groove 23 is greater than 50 bars andthat in the groove 25 is generally so, or the pressure in groove 23 islower than 50 bars, and that in groove 25 is at least equal to 50 bars.This provides the advantage of the jack 5 section can be made ten timessmaller than before, thus facilitating withdrawal of fluid from chamber5a when braking is effectd. Braking is therefore effected more quicklythan before and hence increases safety, not withstanding reduction ofthe size of the parts utilized in the device of the invention.

When, finally, the distributor 15 is in its third position, the fluid isadmitted into the motor 1 through conduit 10, the flow path beingcompleted by the part of the conduit 9 connected to groove 23. If thepressure in the conduits 11 and 10 is high (for example higher than 50bars), the action of the pressure on the face 26 overcomes the bias ofthe spring 17. The passage thereby formed between the edge 22 and theshoulder 21 is without pressure drop and the delivery of the fluid ofthe motor 1 to the tank 7 is also effected without pressure drop. If, onthe other hand the winch tends to race and drive the motor 1, the feedoutput of the said motor drops and the pressure in conduit 10 will belowered, the same applying to as in conduits ll, 18 and 19. The spring17 then pushes the slide 20 (towards the right) and restricts thepassage between the edge 22 and shoulder 21. This passage then acts as arestriction which limits the output of the motor 1, and thus the speedof rotation of said motor 1 and the winch: It will thus be seen that thearrangement described provides speed limit control.

The device of FIG. 1 is of particular advantage when the pump 12 feedsonly the winch. On the other hand, if another receiver, such the jack 28of FIGS. 2 to 4 has also to be fed by pump 12, a momentary drop inpressure in the conduit 18 and consequently in conduit 19 may takeplace. To avoid this the pressure supplied for conduit 40 (see FIG. 2)is tapped from conduit 9 as connected between distributor 15 and valve16 at a location close to the groove 25 so as not to be subject to thepressure fluctuations arising from feed of the jack 28.

FIG. 2 shows the distributor 15 in its first position, the jack 28moreover not being supplied with fluid. The pump 12 delivers fluid 15 totank 7 through conduit 1 l, the distributors 31 and 15 and conduit 14.The winch is not supplied with fluid, since the distributor 15 isolatesthe part of the conduit 9 connected to groove 25 and conduit 10.Moreover, the winch is braked, the lining 2 being in firm abutment onsaid winch, since the chamber 5a is in communication with the tank 7, byconduit 18, distributor 32 and conduit 33.

In the arrangement of FIG. 3, the winch turns (crane hook rising forexample). If the winch turns under load, the pressure is high in groove23 and consequently in the whole of conduit 9 and in conduit 40. Theopening of passage 45 is thus large and brings about practically nopressure drop. Of course, the pressure in the conduits l1 and 18 is thenalso high. Hence, by the action of the jack 5, the lining 2 will beseparated from the winch and the brake will released. If, on the otherhand, the winch turns without load (hook alone), the pressure will below in groove 23, but due to the pressure drop caused by the opening ofthe then restricted passage 45, the pressure in conduit 1 1 remainshigher than a given value, for example 50 bars as previously mentioned.The jack 5 therefore continues to disables the brake of the winch.

Finally, in the arrangement of FIG. 4, the pressure in the groove 25 ispractically zero (connected to the discharge tank 7) and can no longeractuate piston 27, by conduit 40. On the other hand, the feed pressureof the fluid contained in conduit 10 is high, when the motor 1effectively drives the winch and when said latter does not race. Thepressure of the fluid contained in the groove 41 therefore overcomes thebias effect of the spring 17 and maintains at a high value the pressuein the section defined by the passage 46 which is then not subjected topressure drops. The fluid delivered into groove 23 by motor 1accordingly flows without difficulty towards the tank 7. However underthe effect of the load of the, a winch tend to race and drive the motor1, the pressure in the conduit 10 drop and the pressure in the section46 will also drop. The restriction of the passage opening limits theoutput of the motor 1 and thus also the speed of rotation of said motor,and acts thereby as conventional speed limiter, controlled by thepressure of the fluid in the conduit 10 for feeding the motor. The samespeed limiting is applicable to the device shown in FIG. 1, albeit witha hydraulic control of the position of the slide 20, which is moredirect and less sensitive to the possible variations in pressure inconduits 1 l and 18. Although for purpose of disclosure a single elementhas been described for use as a conventional speed limiter and formaintaining the pressure in section 25 at a given value (50 bars in theexample chosen), it is obviously possible to provide these functions bytwo separate elements rather than the single element described.

Similarly, the coupling in the embodiments of FIGS, 2, 3, and 4 theslides of distributors 1S and 32 (which is advantageous from the pointof view of simplicity of operation) is not to be construed limitativelysince obvious variants could be resorted to.

What is claimed is:

1. Device for controlling a winch coupled with a hydraulic drive motor,which comprises at least a two way distributor, a discharge tank, asource of supply of pressurized fluid operatively connected between saiddistributor and said discharge tank, two conduits connected to saiddistributor for selective connection thereby between said discharge tankand said source of pressurized fluid, a third conduit operativelyconnected to said source of pressurized fluid and said distributor, asafety brake having a control member selectively connected by said thirdconduit to said source of pesssurized fluid and to said discharge tank,and a valve interposed in said conduit downstream of the connection ofsaid third conduit with said source of pressurized fluid.

2. Control device according to claim 1, wherein with said distributor inone position thereof, during turning of the winch, the opening of saidvalve is controlled as a function of the pressure of the fluid containedin that part of the first conduit located downstream of said source offluid.

3. Control device according to claim 1, wherein said valve comprises alimiter having a passage section which is adjustable as a function ofmovement ofa slide forming part of the valve.

4. Device according to claim 1, wherein said valve is a calibratedvalve.

1. Device for controlling a winch coupled with a hydraulic drive motor,which comprises at least a two way distributor, a discharge tank, asource of supply of pressurized fluid operatively connected between saiddistributor and said discharge tank, two conduits connected to saiddistributor for selective connection thereby between said discharge tankand said source of pressurized fluid, a third conduit operativelyconnected to said source of pressurized fluid and said distributor, asafety brake having a control member selectively connected by said thirdconduit to said source of pressurized fluid and to said discharge tank,and a calibrated valve interposed in said conduit downstream of theconnection of said third conduit with said source of pressurized fluid.2. Control device according to claim 1, wherein with said distributor inone position thereof, during turning of the winch, the opening of saidvalve is controlled as a function of the Pressure of the fluid containedin that part of the first conduit located downstream of said source offluid.
 3. Control device according to claim 1, wherein said valvecomprises a limiter having a passage section which is adjustable as afunction of movement of a slide forming part of the valve.